* Migrate core/widgetdiv.js to ES6 const/let
* Migrate core/widgetdiv.js to goog.module
* Migrate core/widgetdiv.js to named requires
* clang-format core/widgetdiv.js
* Mark WidgetDiv.DIV as deprecated and refactor callers to use setters/getters
* Fix deprecation date
* Refactor tests to make setDiv() in core/widgetdiv.js test-only
* Fix type annotations for WidgetDiv.DIV and move test cleanup into sharedTestTeardown
* Google changed from an Inc to an LLC.
This happened back in 2017 but we didn’t notice. Officially we should update files from Inc to LLC when they are changed as part of regular edits, but this is a nightmare to remember for the next decade.
* Remove project description/titles from licenses
This is no longer part of Google’s header requirements. Our existing descriptions were useless (“Visual Blocks Editor”) or grossly obselete (“Visual Blocks Language”).
* License no longer requires URL.
* Fix license regexps.